There are two types of diabetes:
Type I occurs when the pancreas either produces no insulin at all, or produces an insignificant amount to handle blood sugar. Type I diabetes is typically found in people under 30 but can occur at any age, and can only be treated with insulin.
Type II occurs when the pancreas produces insulin, but the body has become resistant to it. Obesity is a major cause of insulin resistance. Fat cells are literally stretched and lose their insulin receptors, so they cannot absorb the blood sugar. Type II diabetes can be managed with healthy eating, regular exercise (at least 5-7 days a week), oral medications and/or insulin when necessary.
Diabetes & Cancer
Certain types of cancer may lead to an increased risk of both Type I and Type II diabetes, including pancreas, liver and colorectal cancers. The link between cancer and diabetes is still being explored by researchers.
Although cancer treatments don't typically cause diabetes, high blood sugar must be aggressively managed during treatment. Radiation therapy, steroids and certain chemotherapy drugs can cause blood sugar levels to rise.
For cancer patients with pre-existing diabetes, your doctor may supplement your regular insulin with a fast-acting insulin to bring levels back to normal. For patients who don’t have pre-existing diabetes, high blood sugar levels are managed with a "sliding" insulin regimen, starting out with larger doses and reducing as sugar levels return to normal.
Our Internal Medicine Center has a diabetes program to help cancer patients cope with their disease. Inpatients can be referred by their nurse, dietician or other member of their health care team. Outpatients must be referred by a doctor.
Between 8% and 18% of cancer patients have diabetes, a chronic condition that impacts the ability to regulate blood sugar levels. And, for many patients, diabetes management takes a backseat to cancer treatment. But managing your blood sugar levels can help your overall health.
We spoke with Erma Levy, a research dietitian at MD Anderson, about what cancer patients with diabetes should know.
Can cancer treatment affect blood sugar levels?
Radiation therapy, steroids and some types of chemotherapy may impact your blood sugar levels. And uncontrolled high blood sugar can lead to dehydration, which is a frequent side effect of chemotherapy. Taking extra care to manage your blood sugar levels can help you stay hydrated and feel better during treatment.
Uncontrolled blood sugar levels also can have a negative impact on your other organs. Monitoring your blood sugar levels can help keep them healthy and strong during cancer treatment.
What can cancer patients with diabetes do to improve their health?
If you have Type II diabetes or pre-diabetes (a high risk for developing diabetes), try to manage it through your diet. As your diet allows, focus on a healthy eating plan that’s rich in fruits, vegetables and whole grains and low in fat and calories. You can help keep your blood sugar level in a safe range by ensuring there’s a balance of these foods in your diet throughout the day.
If you’re finding that it’s difficult to eat healthy foods, talk to your doctor or schedule an appointment with a dietitian to find ways to get these foods into your diet. If you’re an MD Anderson patient, your doctor or nurse can refer you to an MD Anderson dietitian.
If you have energy, exercise when possible. This can help you maintain a healthy weight, which plays a key part in controlling your diabetes. Studies have also shown that exercising during treatment can ease side effects and improve quality of life for many patients.
If you’re an MD Anderson patient, be sure to ask about our Internal Medicine Center’s diabetes program. Inpatients can be referred by their nurse, dietitian or other member of their health care team. Outpatients must be referred by an MD Anderson doctor.
What should cancer survivors with diabetes do to lower their risk of recurrence?
People with Type II diabetes are more likely to be diagnosed with cancer than those without diabetes. Researchers aren’t sure if that’s because abnormal insulin levels affect your cancer risk, or because of the other health problems that often accompany diabetes, like obesity. Both diabetes and cancer are related to obesity, inflammation and increased blood sugar.
Fortunately, the same steps that you take to manage your diabetes can also help lower your cancer risk and your risk for recurrence:
- Maintain a healthy diet. Fill two-thirds of your plate with vegetables, fruits and whole grains. Limit the amount of red meat and processed foods you eat. Watch your portion sizes.
- Exercise. Aim for 150 minutes of moderate physical activity or 75 minutes of vigorous exercise each week.
- Limit your alcohol intake. Research shows that heavy drinking damages cells and can lead to cancer. Alcohol is also high in calories and sugar. The National Cancer Institute recommends that women have no more than one drink per day and men have no more than two drinks per day. (A drink serving is defined as 12 ounces of beer, five ounces of wine or 1.5 ounces of liquor.)
Remember, if you have diabetes, the best thing you can do is to make sure your blood sugar levels are under control. That’s true before, during and after cancer treatment.
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